Another XenServer - iscsi gotcha - problems connecting to an QNAP iSCSI target

Xenserver can decide (ie some how be set) to use Chap authentication on discovery

Chris Keim document this at 1bitatatime.blogspot.com.au.

I had this problem with a new Qnap 870 NAS I could connect using a NFS share, but not using iSCSI.

I wanted to use iSCSI as detailed in this post - as a particular disk with a lot of small files would generate errors and hang the Xenserver.

To diagnose

1) connect from another iSCSI initiator (e.g. Windows). Note you can connect, discover targets and connect to a LUN.

2) attempt from Xenserver - both XenCenter and the command line.

3) attempt to connect using iscsadm

[root@xennet2 ~]# iscsiadm  --mode discovery --type sendtargets --portal 192.168.40.2

iscsiadm: Login failed to authenticate with target

iscsiadm: discovery login to 192.168.40.2 rejected: initiator error (02/01), n                                         on-retryable, giving up

iscsiadm: Could not perform SendTargets discovery.

The clue is the error - "failed to authenticate with target". The Qnap NAS doesn't like the authentication passed during the discovery.

To fix - as documented in  Chris' blog, edit the st_config file - in /etc/iscsi/send_targets/192.168.40.2,3260

remove the lines

discovery.sendtargets.auth.username = <user>

discovery.sendtargets.auth.username = <password>

and add:

discovery.sendtargets.authmethod = none

To be persistent (after reboots) make sure /etc/iscsid.conf also has auth.method set to none for discovery.sendtargets (or is commented out).